1. Field of the Invention
The present invention relates to an abrasive substrate provided between a head portion of a carry type abrasive machine which is rotated and vibrated electrically and an abrasive member such as an abrasive paper or an abrasive cloth to be a grinding/abrasive tool, and fixed removably to both the head portion and the abrasive member.
2. Description of the Related Art
In the carry type abrasive machine of this kind, the central part of an abrasive substrate is fixed to a head portion with a bolt and an abrasive member such as an abrasive paper or an abrasive cloth is joined to a surface on the opposite side of a surface on the head side of the abrasive substrate through an adhesive, for example, or is surface joined through a plane fastener (hook and loop fastener) including a male engaging member having a large number of hook-shaped engaging elements and a female engaging member having a loop-shaped engaging element and three of them are integrally fixed. For this reason, the back face of the abrasive member is coated with the adhesive or one of the engaging members of the plain fastener is fixed and the other engaging member of the plain fastener is fixed to the corresponding joined surface of the abrasive substrate.
Usually, the abrasive substrate has such a structure that a rigid doughnut disk-shaped base member and a doughnut disk-shaped elastic plate formed by a sponge are provided integrally and a disk having a large number of hook-shaped, mushroom-shaped, anchor-shaped or conical projections for joining and integrating an abrasive member are further fixed to a surface on the external exposure side of the elastic plate with an adhesive as disclosed in JP-UM(Utility Model)-A-63-196223 and JP-UM-A-64-23221, for example. Alternatively, a rotary disk corresponding to the abrasive substrate is simply constituted by a solid rigid body as disclosed in Japanese Utility Model Registration No. 2585880, for example.
When a carry type abrasive machine is to be operated, a holding portion is usually grasped by one or both hands to push an abrasive member fixed to the surface of a rotating abrasive substrate against a surface to be abraded, thereby carrying out an abrasion work. At this time, generally, the surface to be abraded is not simultaneously abraded with the whole surface of the abrasive member but the abrasion is carried out by moving an abrasive machine to an abraded surface region to be abraded while pushing a partial peripheral edge portion of the abrasive member against the surface to be abraded in respect of the abrasion work in order to uniformly abrade the whole surface to be abraded. More specifically, the abrasive substrate fixing the abrasive member is raised at this side and is inclined forward together with the cary type abrasive machine, thereby performing the abrasion work.
For this reason, in case of an abrasive substrate constituted by a solid rigid body, the shape of an abrasive substrate is used as a conical base and a surface to be abrasive is abraded with a part of an internal or external peripheral surface which is inclined in such a manner that the surface to be abraded can be abraded partially as described in the Japanese Utility Model Registration No. 2585880. Since the abrasive substrate in the abrasive machine is rigid, however, it is elastically deformed with difficulty and a skilled operator can implement the abrasion by uniform pushing force against the surface to be abraded for the first time. On the other hand, the elastic plate described in the JP-UM-A-63-196223 and the JP-UM-A-64-23221 functions as a simple cushion member, and furthermore, has the function of uniformly applying predetermined force through the elastic plate on an abutting surface when the abrasive substrate is inclined obliquely and is pushed against the elastic plate.
JP-UM-A-63-196223, JP-UM-A-64-23221, and Japanese Utility Model Registration No. 2585880 are known as reference documents.
Referring to the structure of the abrasive substrate according to JP-UM-A-63-196223 and JP-UM-A-64-23221, a synthetic resin base member formed of a hard material, an elastic plate formed by a sponge and a hook plate or projection plate are separate members respectively and are to be polymerized and fixed.
For example, in JP-UM-A-63-196223, one side of each of the base member, the elastic plate and the hook plate having a large number of hook-shaped projections is previously joined through an adhesive, and a cup-shaped attachment member is fitted in an attachment hole on a central part and is fastened and fixed with a wood screw through a screw hole formed in the peripheral edge flange portion of the attachment member. The center of the bottom portion of the cup-shaped attachment member is opened to form projections to be indented on the peripheral edge of the opening, a notch is formed in three portions of the circumferential part of the center of a scrubbing brush to be the abrasive member according to the invention, and the indented projections are engaged with the notches of the scrubbing brush for attachment when the scrubbing brush is to be attached to the bottom portion of the cup-shaped attachment member.
According to JP-UM-A-64-23221, moreover, a synthetic resin base member formed of a doughnut disk-shaped hard material, an elastic plate (a sponge plate) having the same shape and a projection plate including a large number of projections having conical diameters on a surface are laminated and integrated through joining, and a scrubbing brush is joined and integrated onto the exposed surface of the projection plate through a removable projection plate. For this reason, a plurality of window portions are formed on the projection plate and the removable projection plates are fitted in the window portions. A large number of male engaging elements of a plain hook and loop fastener are formed on both sides of the removable projection plate. When the removable projection plate is fitted in the window portion of the projection plate, the male engaging element is engaged with and joined to the elastic plate which is exposed to the window portion and the conical projection formed on the surface of the projection plate and the male engaging element formed on the surface of the removable projection plate are engaged and joined to each other in the scrubbing brush attached to the exposed surface of the projection plate.
Thus, the abrasive substrates according to JP-UM-A-63-196223 and JP-UM-A-64-23221 are constituted by a plurality of members. In addition to the manufacture and processing of each member, therefore, the respective members are to be laminated and joined or another member is to be joined in the assembly of the base member. Correspondingly, various costs required for the process are added so that the whole abrasive substrate becomes expensive and an economical burden is imposed.